Webhook Best Practices | Svix Resources

Webhooks are a crucial tool for real-time communication between services. Despite their apparent simplicity, webhooks present complex challenges such as unreliable user endpoints, system reliability, and unique security implications like spoofing, server side request forgery and replay attacks.
Here are some of the best practices we’ve developed through our experience building a secure, reliable, and scalable webhook service for our customers:
How to verify webhook requests in practice: HMAC signature checks over the raw body, constant-time comparison, timestamp tolerance, and secret rotation.
Best practices for sending webhooks at scale: architecture for scalability, security layers, retries and reliability, and the UX features consumers expect.
Best practices for receiving webhooks: verify signatures, block replay attacks with timestamps, handle idempotency, and respond fast with async processing.
Webhook retry best practices: exponential backoff with jitter, a published schedule (8 attempts over 24 hours), a dead letter queue, and idempotent receivers.
Sign webhooks with HMAC-SHA256 over payload and timestamp, reject stale signatures, use HTTPS, and block internal IPs to stop SSRF, replay, and spoofing.
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Svix handles signing, retries, rate limiting, and delivery observability for the webhooks you send to your users, so your team can stay focused on your product.
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